CN109507519A - A kind of earth fault line selection method, apparatus and system - Google Patents
A kind of earth fault line selection method, apparatus and system Download PDFInfo
- Publication number
- CN109507519A CN109507519A CN201811531769.0A CN201811531769A CN109507519A CN 109507519 A CN109507519 A CN 109507519A CN 201811531769 A CN201811531769 A CN 201811531769A CN 109507519 A CN109507519 A CN 109507519A
- Authority
- CN
- China
- Prior art keywords
- current
- zero
- phase
- inverter
- oscillation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/088—Aspects of digital computing
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Mathematical Physics (AREA)
- Theoretical Computer Science (AREA)
- Inverter Devices (AREA)
Abstract
The application discloses a kind of earth fault line selection method, device and system, wherein the described method includes: obtaining the voltage at arc suppression coil both ends in power distribution network, when the voltage at arc suppression coil both ends is all larger than the half of phase voltage, sets delay time；After reaching delay time, the low frequency constant current signal that inverter is injected into power distribution network is obtained, wherein low frequency constant current signal is generated by inverter controller control inverter；Calculate separately the zero-sequence current change in oscillation rate of each transmission line of electricity in power distribution network；Determine that the corresponding transmission line of electricity of maximum value in each route zero-sequence current change in oscillation rate is faulty line；Calculate separately the current oscillation change rate of each phase in faulty line；Determine that the corresponding phase of maximum value in each phase current change in oscillation rate is failure phase.Fault wire and corresponding failure phase simply can accurately be selected using method above-mentioned, and will not influence the measurement accuracy of voltage transformer.
Description
Technical field
This application involves in electric system field of fault detection more particularly to a kind of low-current ground fault line selection side
Method, apparatus and system.
Background technique
With electric utility fast development, the transmission line of electricity in power distribution network is also more and more, leads to the failure of transmission line of electricity
Also more and more.If the failure of transmission line of electricity is checked and repaired not in time, huge economic loss can be brought, simultaneously
Also great inconvenience can be brought to people's lives.
The method of operation of small current neutral grounding is generallyd use in the power distribution network of the 6KV-35KV run at present, small current neutral grounding
The method of operation is using neutral earth-free or through grounding through arc the method for operation.But in neutral earth-free or warp
In the method for operation of grounding through arc, the probability that singlephase earth fault occurs is larger, accounts for about 80% or more.When power distribution network occurs
When singlephase earth fault, remained unchanged in the initial stage usually each alternate voltage swing and phase of failure, three-phase system
Balance is not destroyed, and therefore, it is more than hour that 2 can be run with tape jam route.But with the time that operates with failure
Extend, tape jam route is likely to result in phase fault, even results in whole system paralysis.Therefore, it is necessary to select low current to connect
Faulty line in the method for operation on ground, so as to on-call maintenance, wherein select the fault wire in the method for operation of small current neutral grounding
The process on road is the earth fault line selection of low current.
Existing earth fault line selection method is using signal injection method is based on, in this method, in low current
After singlephase earth fault occurs for earthed system, the phase voltage and residual voltage of faulty line can change, according to its phase voltage
The approximate region of faulty line can be primarily determined with the situation of change of residual voltage；Then restart Injection Signal source, make to inject
Signal source generates a sinusoidal current signal (such as 120Hz, amplitude be about 5A) different from power distribution network intrinsic frequency, and injection is believed
Number source is shorted in the failure phase of voltage transformer secondary side, then injects above-mentioned Injection Signal source to the approximate region of faulty line
The sinusoidal current signal of generation, the signal are coupled in primary system by secondary side, further according to route head end voltage, electric current and event
Injection Signal voltage, electric current at barrier point and the relational expression between fault distance, are calculated final fault distance, determine
Fault point.
But inventor has found in the research process of the application, in existing earth fault line selection method,
To voltage transformer side Injection Signal, it will affect the precision of voltage transformer, power distribution network impacted, meanwhile, the letter of injection
It number can be reduced to several hundred or even tens milliamperes in the amplitude of voltage transformer secondary side, current transformer is difficult to detect the signal
Amplitude, cause earth fault line selection inaccurate.
Summary of the invention
A kind of current earthing fault-line selecting method provided by the embodiments of the present application, apparatus and system, to solve in existing skill
In art, to voltage transformer side Injection Signal, it will affect the precision of voltage transformer, power distribution network impacted, meanwhile, injection
Signal can be reduced to several hundred or even tens milliamperes in the amplitude of voltage transformer secondary side, current transformer is difficult to detect this
The amplitude of signal leads to the problem of earth fault line selection inaccuracy.
In a first aspect, the embodiment of the present application provides a kind of earth fault line selection method, comprising:
The voltage for obtaining arc suppression coil both ends in power distribution network, when the voltage at the arc suppression coil both ends is all larger than phase voltage
When half, delay time is set；
After reaching the delay time, the low frequency constant current signal that inverter is injected into power distribution network is obtained, wherein institute
Low frequency constant current signal is stated to be generated by inverter controller control inverter；
Calculate separately the zero-sequence current change in oscillation rate of each transmission line of electricity in the power distribution network, wherein the zero sequence electricity
Flow the superposition value for the zero-sequence current that change in oscillation rate is the low frequency constant current signal and the transmission line of electricity；
Determine that the corresponding transmission line of electricity of maximum value in the zero-sequence current change in oscillation rate is faulty line；
Calculate separately the current oscillation change rate of each phase in the faulty line, wherein the current oscillation change rate
For the superposition value of the low frequency constant current signal and phase current；
Determine that the corresponding phase of maximum value in the current oscillation change rate is failure phase.
With reference to first aspect, in one implementation, the earth fault line selection method further include:
Request start pulse signal is issued to inverter controller, it is permanent to obtain the low frequency that inverter is injected into power distribution network again
Flow signal.
With reference to first aspect, in one implementation, the inverter injects low frequency constant current signal are as follows: iIt is inverse=Idmsin
(2πfdt)；
Wherein, IdmFor the amplitude of low frequency constant current signal, fdFor the frequency of low frequency constant current signal, t is low frequency constant current signal
Duration.
With reference to first aspect, in one implementation, the calculation method of the zero-sequence current change in oscillation rate are as follows:
The zero-sequence current size for obtaining every 20ms in a cycle of oscillation on kth route, respectively indicates are as follows: Then this route zero-sequence current low-frequency oscillation amplitude size are as follows:
If inverter module does not issue the zero-sequence current under low frequency zero sequence current conditions are as follows:The then zero-sequence current low frequency of kth bar line
Oscillation amplitude change rate are as follows:
With reference to first aspect, in one implementation, the calculation method of the current oscillation change rate are as follows:
If the three-phase on kth route is respectively A, B, C three-phase, obtain every 20ms's in a cycle of oscillation of A phase
Zero-sequence current size, respectively indicates are as follows: IA1、IA2...IAN, then the A phase current low-frequency oscillation amplitude size in the fault wire are as follows:If inverter module does not issue the zero-sequence current under low frequency zero sequence current conditions are as follows:
IA, then the electric current low-frequency oscillation amplitude change rate of A phase are as follows:
The zero-sequence current size for obtaining every 20ms in a cycle of oscillation of B phase, respectively indicates are as follows: IB1、IB2...IBN,
The then B phase current low-frequency oscillation amplitude size in the fault wire are as follows:If inverter
Module does not issue the zero-sequence current under low frequency zero sequence current conditions are as follows: IB, then the electric current low-frequency oscillation amplitude change rate of B phase are as follows:
The zero-sequence current size for obtaining every 20ms in a cycle of oscillation of C phase, respectively indicates are as follows: IC1、IC2...ICN,
The then C phase current low-frequency oscillation amplitude size in the fault wire are as follows:If inverter
Module does not issue the zero-sequence current under low frequency zero sequence current conditions are as follows: IC, then the electric current low-frequency oscillation amplitude change rate of C phase are as follows:
With reference to first aspect, in one implementation, the delay time is more than or equal to 20s.
Second aspect, the embodiment of the present application part provide a kind of low-current ground fault line selection device, comprising:
Voltage obtains module, for obtaining the voltage at arc suppression coil both ends in power distribution network, when the arc suppression coil both ends
When voltage is all larger than the half of phase voltage, delay time is set；
Low frequency constant current signal injection module, for after reaching the delay time, obtaining inverter into power distribution network
The low frequency constant current signal of injection, wherein the low frequency constant current signal is generated by inverter controller control inverter；
Zero-sequence current change in oscillation rate computing module, for calculating separately the zero sequence of each transmission line of electricity in the power distribution network
Current oscillation change rate, wherein the zero-sequence current change in oscillation rate is the low frequency constant current signal and the transmission line of electricity
The superposition value of zero-sequence current；
Faulty line determining module, for determining the corresponding power transmission line of maximum value in the zero-sequence current change in oscillation rate
Road is faulty line；
Current oscillation change rate computing module, the current oscillation for calculating separately each phase in the faulty line change
Rate, wherein the current oscillation change rate is the superposition value of the low frequency constant current signal and phase current；
Failure phase determining module, for determining that the corresponding phase of maximum value in the current oscillation change rate is failure phase.
The third aspect, the embodiment of the present application part provide a kind of small current grounding failure wire selection system, comprising:
Inverter, inverter controller, earthing wire-selecting failed equipment, arc suppression coil voltage transformer, zero sequence current mutual inductor,
Current transformer；
Inverter is by inductance connection arc suppression coil, and after breaking down, arc suppression coil charges to fixation to inverter
Voltage, starts inverter, and the inverter is used to inject low frequency constant current signal into power distribution network；
Inverter controller connects inverter and earthing wire-selecting failed equipment, and the inverter controller is for controlling the inversion
Device generates low frequency constant current signal；
Arc suppression coil voltage transformer connects earthing wire-selecting failed equipment, and the voltage transformer is for measuring arc suppression coil
On voltage, and be transmitted to the earthing wire-selecting failed equipment；
Zero sequence current mutual inductor is arranged on each route of power distribution network, connection ground connection choosing described in the zero sequence current mutual inductor
Line failed equipment, the zero sequence current mutual inductor are used to measure the zero-sequence current of each route of power distribution network, and are transmitted to described connect
Ground route selection failed equipment；
In each phase of current transformer setting in the line, the current transformer connects earthing wire-selecting failed equipment, institute
Current transformer is stated for measuring the electric current in each phase, and is transmitted to the earthing wire-selecting failed equipment.
In conjunction with the third aspect, in one implementation, the inverter includes:
Four IGBT elements, four diodes and simultaneously column capacitance, wherein the diode is fast recovery diode.
A kind of earth fault line selection method, device and system disclosed in the embodiment of the present application, wherein the method
It include: the voltage for obtaining arc suppression coil both ends in power distribution network, when the voltage at the arc suppression coil both ends is all larger than the one of phase voltage
When half, delay time is set；After reaching the delay time, the low frequency constant current letter that inverter is injected into power distribution network is obtained
Number, wherein the low frequency constant current signal is generated by inverter controller control inverter；It is defeated to calculate separately each item in the power distribution network
The zero-sequence current change in oscillation rate of electric line, wherein the zero-sequence current change in oscillation rate is the low frequency constant current signal and institute
State the superposition value of the zero-sequence current of transmission line of electricity；Determine the corresponding power transmission line of maximum value in the zero-sequence current change in oscillation rate
Road is faulty line；Calculate separately the current oscillation change rate of each phase in the faulty line, wherein the current oscillation becomes
Rate is the superposition value of the low frequency constant current signal and phase current；Determine that the maximum value in the current oscillation change rate is corresponding
It is mutually failure phase.
By a kind of earth fault line selection method disclosed in the present application, device and system, passes through and calculate zero sequence electricity
Change in oscillation rate and current oscillation change rate are flowed, simply can accurately select fault wire and corresponding failure phase, and will not
Influence the measurement accuracy of voltage transformer.
Detailed description of the invention
In order to illustrate more clearly of the technical solution of the application, letter will be made to attached drawing needed in the embodiment below
Singly introduce, it should be apparent that, for those of ordinary skills, without creative efforts, also
Other drawings may be obtained according to these drawings without any creative labor.
Fig. 1 is a kind of flow diagram of current earthing fault-line selecting method provided by the embodiments of the present application；
Fig. 2 is a kind of structural schematic diagram of current earthing fault line selection device provided by the embodiments of the present application；
Fig. 3 is a kind of structural schematic diagram of current earthing failure line selection system provided by the embodiments of the present application；
Fig. 4 is the structural schematic diagram of inverter in a kind of current earthing failure line selection system provided by the embodiments of the present application.
Specific embodiment
In order to make the above objects, features, and advantages of the present application more apparent, with reference to the accompanying drawing and it is specific real
Applying mode, the present application will be further described in detail.
A kind of current earthing fault-line selecting method provided by the embodiments of the present application, apparatus and system, to solve in existing skill
In art, to voltage transformer side Injection Signal, it will affect the precision of voltage transformer, power distribution network impacted, meanwhile, injection
Signal can be reduced to several hundred or even tens milliamperes in the amplitude of voltage transformer secondary side, current transformer is difficult to detect this
The amplitude of signal leads to the problem of earth fault line selection inaccuracy.
Referring to Fig.1, a kind of earth fault line selection method is shown, the described method comprises the following steps:
Step 101, the voltage for obtaining arc suppression coil both ends in power distribution network, when the voltage at the arc suppression coil both ends is all larger than
When the half of phase voltage, delay time is set；
Wherein, phase voltage refers to the voltage between the phase line in power distribution network and the neutral conductor (zero curve)；By detecting arc blowout wire
The voltage for enclosing both ends, when its voltage is greater thanI.e. it is believed that singlephase earth fault has occurred, at this time by delay after times phase voltage
Time (typically larger than 20s, to escape the current fluctuation for adjusting circle and transient process of arc suppression coil).
In the application, when singlephase earth fault does not occur for power distribution network, disappear as caused by the unbalanced factor of power distribution network
The voltage at arc coil both ends is very low, usually between zero to tens volts, can be approximately considered no-voltage on inverter capacitor.Occur
After singlephase earth fault, the voltage at arc suppression coil both ends rises very rapidly up to system phase voltage, after arc suppression coil voltage stabilization
It has been quickly accomplished the charging to inverter capacitor, has reached a steady dc voltage (such as Udc=600V), due to disappearing
Arc coil to carry out adjust circle movement, the movement would generally capacitor charging complete one end time in complete, such as 20s in into
Row, therefore certain delay time would generally be set, to guarantee that arc suppression coil is completed to adjust circle movement, reach stable state.
In addition, the effect of charging is so that the capacitor for guaranteeing inverter is established voltage, while providing one to inverter
A alternating-current voltage source guarantees that inverter can inject its expected current signal well.
Preferably, the delay time is more than or equal to 20s.
Step 102, after reaching the delay time, the low frequency constant current letter that inverter is injected into power distribution network is obtained
Number, wherein the low frequency constant current signal is generated by inverter controller control inverter；
Wherein, inverter can be single-phase inverter, the half-bridge converter comprising IGBT.
In this step, select low frequency constant current signal the reason of be: be connected to reactance firstly, since being connected with inverter, reactance
Decay to high-frequency current larger, to low cut smaller, therefore biggish Injection Current can be obtained when output low frequency electric current.
Secondly as usually containing harmonic components in electric current and zero-sequence current in power distribution network, and the harmonic wave is usually fundamental wave integral multiple
Higher hamonic wave, injection low frequency constant current can reduce the influence of zero sequence higher harmonic current.
In this step, after reaching the delay time of setting, the Inverter control module control in inverter controller is single-phase
The IGBT of inverter bridge is connected, it is made to inject a low-frequency ac electric current signal to power distribution network, such as: inject 10Hz's into power distribution network
Alternating current, the alternating current pass through (such as 10KV) bus by arc suppression coil as an additional zero-sequence current of power distribution network
Flow through distribution network transmission line.The duration of the low-frequency ac electric current signal is typically set between 0.5~1s.
Step 103, the zero-sequence current change in oscillation rate of each transmission line of electricity in the power distribution network is calculated separately, wherein institute
State the superposition value for the zero-sequence current that zero-sequence current change in oscillation rate is the low frequency constant current signal and the transmission line of electricity；
In this step, due to the frequency of the low frequency zero-sequence current conveyed from inverter into distribution line by arc suppression coil
Frequency different from the zero-sequence current generated when failure in power distribution network, the superposition of both zero-sequence currents will necessarily generate zero sequence electricity
Flow size hunting of frequency phenomenon, that is to say, that the low frequency constant current signal injected in step 102 can to due to failure generate zero
Sequence electric current generates superposition.
The zero-sequence current change in oscillation rate is that each low frequency zero sequence current oscillation of a period of time in a certain cycle of oscillation becomes
Change amount does not issue the ratio of the zero-sequence current under low frequency zero sequence current conditions with inverter module.
Step 104, determine that the corresponding transmission line of electricity of maximum value in the zero-sequence current change in oscillation rate is faulty line.
In this step, zero sequence change in oscillation rate is maximum, illustrates that fault current is more obvious, therefore can use each route zero sequence electricity
The maximum value in change in oscillation rate is flowed to judge faulty line.
Step 105, the current oscillation change rate of each phase in the faulty line is calculated separately, wherein the electric current vibration
Swing the superposition value that change rate is the low frequency constant current signal and phase current；
In this step, due to the frequency of the low frequency zero-sequence current conveyed from inverter into distribution line by arc suppression coil
The superposition of frequency different from each phase current generated when failure in power distribution network, both electric currents will necessarily generate size of current
Hunting of frequency phenomenon, that is to say, that the low frequency constant current signal injected in step 102 can produce each phase current generated due to failure
Raw superposition.
Each phase current change in oscillation rate is that each low-frequency current of a period of time in the mutually a certain cycle of oscillation vibrates change
Change amount does not issue the ratio of the phase current under low frequency zero sequence current conditions with inverter module.
Step 106, determine that the corresponding phase of maximum value in the current oscillation change rate is failure phase.
In this step, each phase current change in oscillation rate is maximum, illustrates that the phase fault electric current is more obvious, therefore can use each phase
Maximum value in current oscillation change rate judges failure phase.
A kind of earth fault line selection method disclosed in the embodiment of the present application, comprising: obtain arc blowout wire in power distribution network
The voltage for enclosing both ends sets delay time when the voltage at the arc suppression coil both ends is all larger than the half of phase voltage；Reaching
After the delay time, the low frequency constant current signal that inverter is injected into power distribution network is obtained, wherein the low frequency constant current signal
It is generated by inverter controller control inverter；Calculate separately the zero-sequence current change in oscillation of each transmission line of electricity in the power distribution network
Rate, wherein the zero-sequence current change in oscillation rate of the transmission line of electricity is the zero of the low frequency constant current signal and the transmission line of electricity
The superposition value of sequence electric current；Determine that the corresponding transmission line of electricity of maximum value in each route zero-sequence current change in oscillation rate is failure
Route；Calculate separately the current oscillation change rate of each phase in the faulty line, wherein each mutually electricity in the faulty line
Flow the superposition value that change in oscillation rate is the low frequency constant current signal and phase current；It determines in each phase current change in oscillation rate
The corresponding phase of maximum value is failure phase.
By a kind of earth fault line selection method disclosed in the present application, using zero-sequence current change in oscillation rate and electricity
Change in oscillation rate is flowed, simply can accurately select fault wire and corresponding failure phase, and will not influence voltage transformer
Measurement accuracy.
Preferably, the earth fault line selection method further include: issue request trigger pulse to inverter controller
Signal obtains the low frequency constant current signal that inverter is injected into power distribution network again.
In the present embodiment, the low frequency constant current signal injected again into power distribution network can occur after step 103, i.e.,
If the value of the zero-sequence current change in oscillation rate for each transmission line of electricity being calculated has exception, can by inverter controller to
Inverter issues request start pulse signal, the low frequency constant current signal that request inverter is injected into power distribution network again.It can be with
Occur after step step 106, then the low frequency constant current signal injected again into power distribution network executes step 103 to step again
Rapid 106, further increase the accuracy of calculated result.
Preferably, the inverter injects low frequency constant current signal are as follows: iIt is inverse=Idmsin(2πfdt)；
Wherein, IdmFor the amplitude of low frequency constant current signal, fdFor the frequency of low frequency constant current signal, t is low frequency constant current signal
Duration.
In the present embodiment, the entry condition of inverter is:
UExtinguishing arcIndicate the voltage of arc suppression coil, UPExpression system phase voltage, Δ T indicate delay time, τdIndicate low frequency constant current
The duration of signal.
Preferably, the calculation method of the zero-sequence current change in oscillation rate are as follows:
The zero-sequence current size for obtaining every 20ms in a cycle of oscillation on kth route, respectively indicates are as follows: Then this route zero-sequence current low-frequency oscillation amplitude size are as follows:
If inverter module does not issue the zero-sequence current under low frequency zero sequence current conditions are as follows:The then zero-sequence current low frequency of kth bar line
Oscillation amplitude change rate are as follows:
In the present embodiment,Maximum is faulty line.
Preferably, the calculation method of the current oscillation change rate are as follows:
If the three-phase on kth route is respectively A, B, C three-phase, obtain every 20ms's in a cycle of oscillation of A phase
Zero-sequence current size, respectively indicates are as follows: IA1、IA2...IAN, then the A phase current low-frequency oscillation amplitude size in the fault wire are as follows:If inverter module does not issue the zero-sequence current under low frequency zero sequence current conditions are as follows:
IA, then the electric current low-frequency oscillation amplitude change rate of A phase are as follows:
The zero-sequence current size for obtaining every 20ms in a cycle of oscillation of B phase, respectively indicates are as follows: IB1、IB2...IBN,
The then B phase current low-frequency oscillation amplitude size in the fault wire are as follows:If inverter
Module does not issue the zero-sequence current under low frequency zero sequence current conditions are as follows: IB, then the electric current low-frequency oscillation amplitude change rate of B phase are as follows:
The zero-sequence current size for obtaining every 20ms in a cycle of oscillation of C phase, respectively indicates are as follows: IC1、IC2...ICN,
The then C phase current low-frequency oscillation amplitude size in the fault wire are as follows:If inverter
Module does not issue the zero-sequence current under low frequency zero sequence current conditions are as follows: IC, then the electric current low-frequency oscillation amplitude change rate of C phase are as follows:
In the present embodiment,WithIn the corresponding phase of maximum value be failure phase.
Referring to Fig. 2, a kind of low-current ground fault line selection device is shown, described device includes:
Voltage obtains module 201, for obtaining the voltage at arc suppression coil both ends in power distribution network, when the arc suppression coil both ends
Voltage when being all larger than the half of phase voltage, set delay time；
Low frequency constant current signal injection module 202, for after reaching the delay time, obtaining inverter to power distribution network
The low frequency constant current signal of middle injection, wherein the low frequency constant current signal is generated by inverter controller control inverter；
Zero-sequence current change in oscillation rate computing module 203, for calculating separately in the power distribution network each transmission line of electricity
Zero-sequence current change in oscillation rate, wherein the zero-sequence current change in oscillation rate is the low frequency constant current signal and the power transmission line
The superposition value of the zero-sequence current on road；
Faulty line determining module 204, for determining that the maximum value in the zero-sequence current change in oscillation rate is corresponding defeated
Electric line is faulty line.
Current oscillation change rate computing module 205, for calculating separately the current oscillation of each phase in the faulty line
Change rate, wherein the current oscillation change rate is the superposition value of the low frequency constant current signal and phase current；
Failure phase determining module 206, for determining that the corresponding phase of maximum value in the current oscillation change rate is failure
Phase.
Referring to Fig. 3, a kind of small current grounding failure wire selection system is shown, the system comprises:
Inverter 301, inverter controller 302, earthing wire-selecting failed equipment 303, arc suppression coil voltage transformer 304, zero
Sequence current transformer 305, current transformer 306；
Inverter is by inductance connection arc suppression coil, and after breaking down, arc suppression coil charges to fixation to inverter
Voltage, starts inverter, and the inverter is used to inject low frequency constant current signal into power distribution network；
Wherein, inverter used in this application is connected between two taps of arc suppression coil, is mentioned by arc suppression coil
For energy；Only after singlephase earth fault occurs for power distribution network or three-phase imbalance is just to be able to achieve to charge to inverter,
It is not the energy supply charging of inverter capacitor in normal three-phase symmetrical.It is not only an inverter, does not need external electrical
Source power supply, as long as and failure exist, external power supply there is, and external power supply disappears after failure vanishes.
In addition, Injection Signal source used herein is can be changed by the part between inverter and two taps of arc suppression coil
What voltage source was realized jointly.
Inverter controller connects inverter and earthing wire-selecting failed equipment, and the inverter controller is for controlling the inversion
Device generates low frequency constant current signal；
Arc suppression coil voltage transformer connects earthing wire-selecting failed equipment, and the voltage transformer is for measuring arc suppression coil
On voltage, and be transmitted to the earthing wire-selecting failed equipment；
Zero sequence current mutual inductor is arranged on each route of power distribution network, connection ground connection choosing described in the zero sequence current mutual inductor
Line failed equipment, the zero sequence current mutual inductor are used to measure the zero-sequence current of each route of power distribution network, and are transmitted to described connect
Ground route selection failed equipment；
In each phase of current transformer setting in the line, the current transformer connects earthing wire-selecting failed equipment, institute
Current transformer is stated for measuring the electric current in each phase, and is transmitted to the earthing wire-selecting failed equipment.
Wherein, end voltage and inverter output current that circuit control device passes through the shunt capacitor in measurement inverter
It realizes the tracing control to the output low frequency constant current signal of inverter, while keeping the voltage at shunt capacitor both ends in inverter
Reach it and set pursuit gain, this is controlled by the trigger pulse to the inverter bridge IGBT in inverter to realize.
In the present embodiment, ground fault line selection device obtains each phase of voltage signal, non-fault line at arc suppression coil both ends
Current signal and each phase of zero sequence current signal, faulty line current signal and zero sequence current signal.Sentenced by analytical calculation
It is disconnected to have earth fault line and failure phase.Simultaneously also by issuing request start pulse signal to circuit control device, it is desirable that control
Inverter processed issues low frequency constant current signal again, increases the accuracy of judgement.
Referring to Fig. 4, a kind of structure of inverter is shown, the inverter includes:
Four IGBT elements, four diodes and simultaneously column capacitance, wherein the diode is fast recovery diode.
As shown in figure 4, L1、L2For two small inductors for connecting inverter, effect is the low-frequency voltage for exporting inverter
Signal is changed into current signal, K1、K2、K3、K4For 4 IGBT (Insulated Gate for constructing inverter
BipolarTransistor, insulated gate bipolar transistor) element, D1、D2、D3、D4For 4 fast recovery diodes.It and K1、
K2、K3、K4Inverter, C are constituted togethereFor inverter and column capacitance, value can be 104~105It is chosen between μ F.Wherein, K1
And D1Compose in parallel the first circuit, K2And D2Compose in parallel second servo loop, K3And D3Compose in parallel tertiary circuit, K4And D4In parallel group
At the 4th circuit, then the first circuit, second servo loop, tertiary circuit and the 4th circuit in series form the 5th circuit, the 5th circuit
Again with CeCompose in parallel inverter structure；Arc suppression coil is turn-adjusting coil, taps the inverter usually between 9~24
Two connection reactance L1、L2It is generally connected between 6% or so two taps that 10KV arc suppression coil always divides.L1、L2It takes
Value is usually between 1~10mH.
Same and similar part may refer to each other between each embodiment in this specification.Implement especially for device
For example, since it is substantially similar to the method embodiment, so being described relatively simple, related place is referring in embodiment of the method
Explanation.
Combine detailed description and exemplary example that the application is described in detail above, but these explanations are simultaneously
It should not be understood as the limitation to the application.It will be appreciated by those skilled in the art that without departing from the application spirit and scope,
A variety of equivalent substitution, modification or improvements can be carried out to technical scheme and embodiments thereof, these each fall within the application
In the range of.The protection scope of the application is determined by the appended claims.
Claims (9)
1. a kind of earth fault line selection method characterized by comprising
The voltage for obtaining arc suppression coil both ends in power distribution network, when the voltage at the arc suppression coil both ends is all larger than the half of phase voltage
When, set delay time；
After reaching the delay time, the low frequency constant current signal that inverter is injected into power distribution network is obtained, wherein described low
Frequency constant current signal is generated by inverter controller control inverter；
Calculate separately the zero-sequence current change in oscillation rate of each transmission line of electricity in the power distribution network, wherein the zero-sequence current vibration
Swing the superposition value for the zero-sequence current that change rate is the low frequency constant current signal and the transmission line of electricity；
Determine that the corresponding transmission line of electricity of maximum value in the zero-sequence current change in oscillation rate is faulty line；
Calculate separately the current oscillation change rate of each phase in the faulty line, wherein the current oscillation change rate is institute
State the superposition value of low frequency constant current signal and phase current；
Determine that the corresponding phase of maximum value in the current oscillation change rate is failure phase.
2. earth fault line selection method according to claim 1, which is characterized in that the small current grounding fault choosing
Line method further include:
Request start pulse signal is issued to inverter controller, obtains the low frequency constant current letter that inverter is injected into power distribution network again
Number.
3. earth fault line selection method according to claim 1, which is characterized in that
The inverter injects low frequency constant current signal are as follows: iIt is inverse=Idmsin(2πfdt)；
Wherein, IdmFor the amplitude of low frequency constant current signal, fdFor the frequency of low frequency constant current signal, t is continuing for low frequency constant current signal
Time.
4. earth fault line selection method according to claim 1, which is characterized in that
The calculation method of the zero-sequence current change in oscillation rate are as follows:
The zero-sequence current size for obtaining every 20ms in a cycle of oscillation on kth route, respectively indicates are as follows: Then this route zero-sequence current low-frequency oscillation amplitude size are as follows:
If inverter module does not issue the zero-sequence current under low frequency zero sequence current conditions are as follows:The then zero-sequence current low frequency of kth bar line
Oscillation amplitude change rate are as follows:
5. earth fault line selection method according to claim 4, which is characterized in that
The calculation method of the current oscillation change rate are as follows:
If the three-phase on kth route is respectively A, B, C three-phase, the zero sequence of every 20ms in a cycle of oscillation of A phase is obtained
Size of current respectively indicates are as follows: IA1、IA2...IAN, then the A phase current low-frequency oscillation amplitude size in the fault wire are as follows:If inverter module does not issue the zero-sequence current under low frequency zero sequence current conditions are as follows:
IA, then the electric current low-frequency oscillation amplitude change rate of A phase are as follows:
The zero-sequence current size for obtaining every 20ms in a cycle of oscillation of B phase, respectively indicates are as follows: IB1、IB2...IBN, then should
B phase current low-frequency oscillation amplitude size in fault wire are as follows:If inverter module
The zero-sequence current under low frequency zero sequence current conditions is not issued are as follows: IB, then the electric current low-frequency oscillation amplitude change rate of B phase are as follows:
The zero-sequence current size for obtaining every 20ms in a cycle of oscillation of C phase, respectively indicates are as follows: IC1、IC2...ICN, then should
C phase current low-frequency oscillation amplitude size in fault wire are as follows:If inverter module
The zero-sequence current under low frequency zero sequence current conditions is not issued are as follows: IC, then the electric current low-frequency oscillation amplitude change rate of C phase are as follows:
6. earth fault line selection method according to claim 1, which is characterized in that
The delay time is more than or equal to 20s.
7. a kind of low-current ground fault line selection device characterized by comprising
Voltage obtains module, for obtaining the voltage at arc suppression coil both ends in power distribution network, when the voltage at the arc suppression coil both ends
When being all larger than the half of phase voltage, delay time is set；
Low frequency constant current signal injection module is injected for after reaching the delay time, obtaining inverter into power distribution network
Low frequency constant current signal, wherein the low frequency constant current signal by inverter controller control inverter generate；
Zero-sequence current change in oscillation rate computing module, for calculating separately the zero-sequence current of each transmission line of electricity in the power distribution network
Change in oscillation rate, wherein the zero-sequence current change in oscillation rate is the zero sequence of the low frequency constant current signal and the transmission line of electricity
The superposition value of electric current；
Faulty line determining module, the corresponding transmission line of electricity of maximum value for determining in the zero-sequence current change in oscillation rate are
Faulty line；
Current oscillation change rate computing module, for calculating separately the current oscillation change rate of each phase in the faulty line,
Wherein, the current oscillation change rate is the superposition value of the low frequency constant current signal and phase current；
Failure phase determining module, for determining that the corresponding phase of maximum value in the current oscillation change rate is failure phase.
8. a kind of small current grounding failure wire selection system characterized by comprising
Inverter, inverter controller, earthing wire-selecting failed equipment, arc suppression coil voltage transformer, zero sequence current mutual inductor, electric current
Mutual inductor；
Inverter is by inductance connection arc suppression coil, and after breaking down, arc suppression coil charges to fixed voltage to inverter,
Start inverter, the inverter is used to inject low frequency constant current signal into power distribution network；
Inverter controller connects inverter and earthing wire-selecting failed equipment, and the inverter controller is produced for controlling the inverter
Raw low frequency constant current signal；
Arc suppression coil voltage transformer connects earthing wire-selecting failed equipment, and the voltage transformer is for measuring on arc suppression coil
Voltage, and it is transmitted to the earthing wire-selecting failed equipment；
Zero sequence current mutual inductor is arranged on each route of power distribution network, connection earthing wire-selecting event described in the zero sequence current mutual inductor
Fault device, the zero sequence current mutual inductor are used to measure the zero-sequence current of each route of power distribution network, and are transmitted to the ground connection choosing
Line failed equipment；
In each phase of current transformer setting in the line, the current transformer connects earthing wire-selecting failed equipment, the electricity
Current transformer is used to measure the electric current in each phase, and is transmitted to the earthing wire-selecting failed equipment.
9. small current grounding failure wire selection system according to claim 8, which is characterized in that the inverter includes:
Four IGBT elements, four diodes and simultaneously column capacitance, wherein the diode is fast recovery diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811531769.0A CN109507519B (en) | 2018-12-14 | 2018-12-14 | Low-current ground fault line selection method, device and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811531769.0A CN109507519B (en) | 2018-12-14 | 2018-12-14 | Low-current ground fault line selection method, device and system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109507519A true CN109507519A (en) | 2019-03-22 |
| CN109507519B CN109507519B (en) | 2021-01-26 |
Family
ID=65752478
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811531769.0A Active CN109507519B (en) | 2018-12-14 | 2018-12-14 | Low-current ground fault line selection method, device and system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109507519B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110568313A (en) * | 2019-09-11 | 2019-12-13 | 北京智创骏驰电气科技有限公司 | single-phase earth fault positioning method and system for small current earthing system |
| CN110780233A (en) * | 2019-12-06 | 2020-02-11 | 国网江苏省电力有限公司南通供电分公司 | Circuit electric leakage detection system based on signal injection |
| CN111624439A (en) * | 2020-05-18 | 2020-09-04 | 南方电网科学研究院有限责任公司 | Fault line selection method based on inverter injection characteristic signal |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060125486A1 (en) * | 2004-12-10 | 2006-06-15 | Premerlani William J | System and method of locating ground fault in electrical power distribution system |
| CN101369727A (en) * | 2008-10-15 | 2009-02-18 | 中国矿业大学 | Route selection method aiming at electric arc ground fault |
| CN104218563A (en) * | 2014-09-26 | 2014-12-17 | 福州大学 | Power distribution network fault arc extinction method by connecting neutral point to the ground through multi-level converter |
| CN104898029A (en) * | 2015-06-25 | 2015-09-09 | 湖北工业大学 | Similarity single-phase earth fault line selection method based on active full compensation arc suppression control |
| CN107064733A (en) * | 2017-03-15 | 2017-08-18 | 长沙理工大学 | Power distribution network flexible ground device single-phase earth fault line selection and arc extinguishing method |
| CN107482607A (en) * | 2017-10-16 | 2017-12-15 | 长沙理工大学 | It is a kind of to present type flexible ground device, failure arc extinguishing method and its DC side voltage control method and system for power distribution network |
| CN108347046A (en) * | 2017-01-24 | 2018-07-31 | 中国石油化工股份有限公司 | A kind of small current grounding fault New Method of Active Electronic Compensation and system |
-
2018
- 2018-12-14 CN CN201811531769.0A patent/CN109507519B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060125486A1 (en) * | 2004-12-10 | 2006-06-15 | Premerlani William J | System and method of locating ground fault in electrical power distribution system |
| CN101369727A (en) * | 2008-10-15 | 2009-02-18 | 中国矿业大学 | Route selection method aiming at electric arc ground fault |
| CN104218563A (en) * | 2014-09-26 | 2014-12-17 | 福州大学 | Power distribution network fault arc extinction method by connecting neutral point to the ground through multi-level converter |
| CN104898029A (en) * | 2015-06-25 | 2015-09-09 | 湖北工业大学 | Similarity single-phase earth fault line selection method based on active full compensation arc suppression control |
| CN108347046A (en) * | 2017-01-24 | 2018-07-31 | 中国石油化工股份有限公司 | A kind of small current grounding fault New Method of Active Electronic Compensation and system |
| CN107064733A (en) * | 2017-03-15 | 2017-08-18 | 长沙理工大学 | Power distribution network flexible ground device single-phase earth fault line selection and arc extinguishing method |
| CN107482607A (en) * | 2017-10-16 | 2017-12-15 | 长沙理工大学 | It is a kind of to present type flexible ground device, failure arc extinguishing method and its DC side voltage control method and system for power distribution network |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110568313A (en) * | 2019-09-11 | 2019-12-13 | 北京智创骏驰电气科技有限公司 | single-phase earth fault positioning method and system for small current earthing system |
| CN110568313B (en) * | 2019-09-11 | 2022-01-18 | 荆平 | Single-phase earth fault positioning method and system for small current earthing system |
| CN110780233A (en) * | 2019-12-06 | 2020-02-11 | 国网江苏省电力有限公司南通供电分公司 | Circuit electric leakage detection system based on signal injection |
| CN111624439A (en) * | 2020-05-18 | 2020-09-04 | 南方电网科学研究院有限责任公司 | Fault line selection method based on inverter injection characteristic signal |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109507519B (en) | 2021-01-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107918079B (en) | Power distribution network single-phase earth fault positioning method and system based on sweep frequency injection | |
| CN109507519A (en) | A kind of earth fault line selection method, apparatus and system | |
| CN106353642A (en) | Small current grounded line gating and tuning method based on arc suppression coil access control short time heteromorphic signal | |
| CN1673764A (en) | Switch selecting and moment measuring method for single phase earthing fault of small current earthed system | |
| CN103368167A (en) | Single-phase earth fault fundamental current full compensation device and method | |
| CN109782122A (en) | A kind of detection method of S Injection Signal | |
| CN104198798A (en) | Method for measuring resonance of fault capacitive current of petersen coil device | |
| Wang et al. | Identification of the faulted distribution line using thyristor-controlled grounding | |
| CN111624439A (en) | Fault line selection method based on inverter injection characteristic signal | |
| CN105093064B (en) | Power distribution network wide area Fault Locating Method | |
| CN113872146A (en) | Neutral point hybrid ground fault regulation and control device and method | |
| CN107238780B (en) | The compensation of ground power grid self-adaption route selection method classified using Rough Set | |
| CN108493916B (en) | A kind of suppressing method and its suppression circuit of power distribution network zero sequence overvoltage | |
| CN112014768A (en) | Method and system for detecting faults of underground power-losing circuit based on additional power supply | |
| CN105738677B (en) | A kind of power network capacitive earth current detection method | |
| CN105093162A (en) | Method and device for calibrating measurement error of electric energy meter under pulse train interference condition | |
| Long et al. | A new technique to detect faults in de-energized distribution feeders—Part I: Scheme and asymmetrical fault detection | |
| CN105375447A (en) | A three-phase reclosing time sequence setting method for reducing distance protection misoperation rate in alternating current and direct current systems | |
| CN111398732B (en) | Power distribution network system based on active control of ground potential fluctuation and fault identification method thereof | |
| CN111521964A (en) | Electromagnetic field test platform for simulating power grid incident disturbance | |
| CN110927551A (en) | Short-circuit current test loop of thyristor converter valve component | |
| CN107422229B (en) | Transmission system fault detection method and device, computer storage medium and equipment | |
| Padungsin et al. | The Comparison Study of Harmonic Detection Algorithms for Single-Phase Power Systems | |
| CN209673891U (en) | A kind of ferromagnetic resonance device for identifying for power distribution network | |
| CN109885889B (en) | Simulation evaluation method and system for same-series dynamic reactive power compensation device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |